Process for the manufacture of cellulose acetate and product thereof



* The cellulose sequently subject Patented Nov. 7, rose V 1,934,450'1 PROCESS not: THE MANUFACTURE' or" CELLULOSE A THEREOF Samuel E. Sheppard and V lLeon ETATE AND PRODUCT,

Eberlin, l I

Rochester, N.*Y.,,,assignors to EastmanlKodak Comp ny, N ew York No Drawing;

Rochester, N. Y., a corporation of Application. January .3, 1929 V Serial No. 330,018

- I ms, a. 23-243) r -This invention relates to cellulose acetate and to the preparation thereof for use in the manu= facture of various products, suchias artificial silk,.photographic film support, lacquers, plastic -5 ma'ssesa'nd the like. 1 Cellulose acetate is produced by the actionof acetylating agents on cellulose in the presence of catalysts; The'reaction mixture maybesubjected subsequently to a hydrolyzing treatment. acetate, either hydrolyzed or. in its may be separated fromthe reaction mixture .by precipitation, spray drying or otherwise. The product is a dry powder which is subsequently dissolved or mixed with plastifiers initial form,

15 or other agents and utilized in the production of various solid and liquid products. Cellulose acetate, particularly if prepared by spray drying, is a powdered material. subject to dusting and is highly electro-static. It is con-v to hazards such as dust. explosions. Y 7 It is the object of the present invention to provide cellulose acetate in the form of. a non-dusting powder adapted to retain electro-static '25 charges and tothus avoid. the hazards mentioned.

.Further objects of the invention are to incorporate with the cellulose acetate, softeningor plastifying agents which, facilitate thepreparationof plastic and other compounds, and a meth- 0d of preparing cellulose acetate in a form which adapts it for subsequent commercial use.

We have discovered that the tendency of cel lulose acetate to dust and to form explosive mix-,

tures with aircan be, overcome by. incorporating with. the powder certain oleaginous materials including oils, fats, and waxes. These materials afford the additional advantage, 'in combination with cellulose acetate, agents or plastifiers. 1 They do not, therefore, 40 affect the'cellulose acetate adversely with reference to its varioususes and, infact, facilitate the incorporation of the powder in various compositions, it being generally necessary to include softening or plastifying agents in such compositions. p i

Incarrying out the invention, the cellulose acetate is recovered from the reaction mixture in any suitable manner, for example, by precip-, y as .de scribed for example, in the U. S. patent by Webb,

itation 1 or preferably by spray No. 1,516,225, or by the preparation of the .cellulose acetate in the form of a very finely divided porous powder as described in our co pendingapplicati on, Serial No. 330,019, filed January 3, 1929.

The powdered cellulose acetate and similar products.

in that they are softening 1 produced by precipitation or by spray drying is washedwith water" to separate contaminating constituents which are the by-products of '"the' 'reaction. The powder thus prepared "in a substantially pure condition'is then subjected to .a liquid in which the oleaginous material is, incorporated, either as a solution or-partial'solution-orpreferably as an emulsion. The powder is thoroughly agitated in this liquid agent to deposition the surfaces of the particles films of theoleagin'ous material. The surplus liquid is then removed,=preferably by fi1-' trationfleaving the particles of powder with the coatingfilms which prevent dusting, retain e1ec-- tro-static charges, thus preventing explosions when the finely divided material is mingled with air in any subsequent handling oroperation; The

films beingof material-capable of acting as a softening or plastifying agent, facilitate the m corporationof the powder in various mixtures and compositions forthe production of plastic Various oleaginous materials may be used for the purpose of the invention, including among, others, castoroil, oleic acid, and monochlornaph thaleneor organic esters of high molecular weight 8 0 insoluble in Water and being substantially a nonsolvent of the cellulose acetate, such, for example,

as sodium oleate or methylmargarate. These 7 materials are readily incorporated in solution, partial solution, or in emulsions and can be deg posited in the manner describedon the particlesof cellulose acetate. They are softening agents 1 or plastifiers and, when deposited on theparticles, theyprevent dusting and retain electro-static charges. I

' In carrying out the invention, we prefer to prepare an emulsion of the oleaginous material by mixing the latter with Water, ammonia, and a suitable solvent, for example, ethyl alcohol. The

emulsion is produced by introducing the mixture" to an homogenizer or emulsifier of which various types are available. After the cellulose acetate powder, has been substantially freed from contaminating constituents, it is subjected toa final wash and a proportion of the emulsion is introduced with the water employed for the final wash. The cellulose acetete powder is agitated with the water containing the emulsion for a sufficient period to accomplish the desired coating and to remove final. traces of undesirable constituents in the powder. The water is removed then by filtering, centrifuging, or otherwise and may be again used 'in treating additional batches of the cellulose v acetate after addition of a sufiicient quantity of the emulsion. The powder is .dried to remove water. The particles remain coated with a thin layer of film of the oleaginous material, the thicl ness of the film depending upon the concentration of the final wash with respect to'the emulsion.

7 We have found it convenient and satisfactoryto Castor oil .180" Ethyl alcohol 300 Ammonia (28%) 200 v n tended purpose.

scribed may be thoroughly agitated with 300 grams of spray-dried cellulose acetate powdery The excess liquid is then removed, for example, by a suction filter, and the powder is dried. The powder will carry about 1%v of castor oil and is free from tendency to dust.' I

Example II .-In place of the emulsion as described, the following constituents may be employed:

7 cc. Oleic acid '70 Ammonia (28%) 80 Ethyl alcohol .350 Water -1 1500 This emulsion is agitated with 300 grams of spray-dried cellulose acetate powder.v When the surplus liquid has been removed by filtration or otherwise, the powder is dried and contains about V v I Monochlornaphthalene 150 Castor oil l 40 Ammonia (28%); '40

- Wateri 4000 1.8% oleic acid, It is likewise free from tendency to dust. I

Example III .An emulsion including the following ingredients may be used:

This emulsion is iagitated with' 500 grams of dry cellulose acetate powder. The surplus liquid is removed by filtration or'otherwise and the powder is again dried. It includes about 1 2% of monochlornaphthalene and is completely nondusting. Monochlornaphthalene is, moreover, a plastifier which can be used advantageously in preparing plastic and other compounds including cellulose acetate. Cellulose acetate powder, including monochlornaphthalene in the proportion indicated, may be combined'with'various solvents to produce plastic compositions. I Although this invention primarily describes the prevention of'dusting of cellulose acetate powder,

fthemethod is'obviously applicable to all cellulose colloidalized bodies such as cellulose esters or ethers or the dissolved celluloseproductssuch as viscose when these materials are prepared inv the comminuted or powdered form.

As hereinbefore indicated, the invention is not limited to the particular oleaginous materials tions. 7

' in powdered form,

For example, the emulsion dementioned herein. The term oleaginous materials asused in the claims, includes oils, fats, and waxes, which are non-solvents for cellulose acetates, are not detrimental in compositions including cellulose acetates'and preferably are suitableas softeners or plastifiers in such composi- --Various changes may be made therefore in the procedure and the materials employed for the purpose of the invention without departing therefrom or sacrificing any of the advantages thereof. I-Iavingthus described our invention, what we claim as new and desire to secure by Letters Patent is:

' 1. 'A product comprising a cellulose colloidalized product in powdered form, the particles hav- ,ing an oleaginous film which prevents dusting and retains electro-static charges.

2. A product comprising a cellulose derivative the particles having an oleaginous :filmwhich prevents-dusting and retains electro-staticcharges. 2 g

3. Afproduct comprising acellulose ester" in powdered form,'the particles having an 01eagi-; nous film which prevents dusting and retains elec-' tro-static charges. j

4. A product comprising a cellulose acetate in powdered form, the particles having an ole.- aginous film which preventsdusting and retains electro-static' charges. U

5. A product comprising cellulose'acetate' in powdered form, thefparticles having a film of an oleaginous softening agent.

6. A product comprising cellulose acetate in powdered form, the particles having a film of castor oil.

'7. A method of preparing a cellulose colloidalized product in powdered form which comprises depositing on the particles a film ofoleaginous material. I

8. A method of preparing a cellulose colloidalized productin powdered form which comprises subjecting the product to an emulsion of an oleaginous material. r

9.-A method of preparing a cellulose-ester in powdered form' which comprises subjecting thepowder to an emulsion of an'oleaginous material.

10. A. method of preparing cellulose acetate which comprises separatingthe cellulose acetate from 'the'reaction mixture in powdered form, washing the'powder to remove contaminating constituents and finally depositingon the particles a film of oleaginous material;

'11. A method. of preparing cellulose acetate which comprises separating the cellulose acetate; from the reaction mixture in powdered form, washing the powder to remove contaminating. constituents and finally depositing on the particles a film of an oleaginous softening agent.

12 A,method of preparing cellulose acetate which comprisesseparating the cellulose acetate from the reaction mixture in-powdered form, washing the powder to remove contaminating constituents and finally depositing on the particles a film of castor oil. 7

" 13. A method of preparing cellulose'acetate which comprises separating the cellulose acetate from the reaction mixture'in powdered form, washing the powder to remove contaminating constituents and finally subjecting the powder to the action of an emulsion containing an oleaginous material.

' 14. A method of preparing cellulose acetate which comprises separating the cellulose acetate from the'reac'tion mixture in powdered form.

l6. A product comprising a cellulose ester in,

powdered form, the particles having thereon a film of a material which is substantially insoluble in water and substantially a non-solvent of the cellulose ester selected from the group consisting of higher fatty acids and their oleaginous derivatives. v r

17. A product comprising cellulose acetate in powdered form, the particles having thereon a film or" a material which is substantially insoluble in water and substantially a non-solvent of the acetate selected from the group consisting of higher fatty acids and their oleaginous derivatives.

18. A method of preparing a cellulose ester.

in powdered form which comprises subjecting the powder to an emulsion of material selected from the group consisting of higher fatty acids and their oleaginous derivatives.

19. A method of preparing cellulose acetate in the powder to an emulsion of material selected from the group consisting of higher fatty acids" and their oleaginous derivatives.

20.'A product comprising a cellulose ester in powdered form, the particles having thereon a powdered form which comprises subjectingfilm of a substance which is substantially insoluble in water and substantially a non-solvent of sisting of V monochlornaphthalene, higher fatty acids and their oleaginous derivatives.

- 21. A product'comprising cellulose acetate in powdered form, the particles having thereon a film of a substance which is substantially insoluble in water andsubstantially a non-solvent of the acetate, selected from the group consisting the cellulose ester, selected from the groupcon- V of monochlornaphthalene, higher fatty acids and their oleaginous derivatives.

22. A method of preparing a cellulose ester in powdered formwhich comprises subjecting the powder to an emulsion of a substance selected from the group consisting of monochlornaphthalene, higher fatty acids and their oleaginous derivatives. a

23. A method of preparing cellulose acetate in powdered form which comprises subjecting the powder to an emulsion of a substance selected from the group consisting of monochlornaphthalene, higher fatty acids and their oleaginous derivatives. j

24. A product comprising a cellulose ester in film of a material selected from the group consisting of-castor oil, oleic acid, monochlornaphthalene, sodium oleate, andmethyl margarate.

25. A product comprising cellulose acetate in powdered form, the particles having thereon a film of a substance selected from the group consisting of castor oil, oleic acid, monochlornaphthalene, sodium oleate, and methyl margarata SAMUEL, E. SHEPPARD. LEON W. EBERLIN.

100 powdered form, the particles having thereon a 

